理不尽|りふじんrifujin[2]nakadaka (mid-high)

1. na-adjective, noununreasonable; irrational; outrageous; absurd

• Synonym不合理ふごうりNeutralPoints to what defies logic or reason; the stress is on illogic, while 「理不尽」 stresses unreasonableness you cannot accept.
• Synonym不条理ふじょうりNeutralAbsurd, against all reason, as in 「人生の不条理」; carries a philosophical flavor that 「理不尽」 lacks.
• Synonym非合理ひごうりNeutralIrrational, non-rational; leans philosophical or economic and lacks the sense of outrageousness in 「理不尽」.
• Synonym無茶むちゃCasualColloquial: reckless, going too far; stresses rashness and does not stress being high-handed.
• SynonymめちゃくちゃCasualColloquial and strong: chaotic, utterly without reason; can also describe a state of disorder.
• RelatedめちゃめちゃCasualColloquial and strong: chaotic and utterly without reason; can also describe a state of disorder.
• Related筋違いすじちがいNeutralAlso a sprain or crick. For the unreasonable sense, the point is aiming at the wrong target, as in 「筋違いな恨み」.
• Related非常識ひじょうしきNeutralLack of common sense; stresses going against accepted norms and is said mainly of people's words and deeds.
• Related荒唐無稽こうとうむけいNeutralA four-character idiom for wild nonsense with no basis in fact; stresses being divorced from reality.
• RelatedむちゃくちゃCasualColloquial; an intensified 「無茶」. Stresses acting wildly, doing things without reason.
• Related馬鹿らしいばからしいNeutralColloquial: foolish and laughable, stressing that something is pointless, not worth the trouble.
• Related非論理的ひろんりてきNeutralDescribes thinking that does not follow logic; it never suggests the other party is being high-handed, as 「理不尽」 can.
• RelatedばかばかしいNeutralAbsurd to the point of laughable and not worth bothering with; stresses silliness, not the other party's unreasonableness.
• Related阿呆らしいあほらしいCasualColloquial, heard often in Kansai: so silly it is laughable; stresses foolishness rather than unreasonableness.
• Related馬鹿げたばかげたNeutralColloquial; the prenominal form, used before a noun: foolish, absurd.
• RelatedべらぼうCasualEdo-period colloquialism with a rough edge: excessive or absurd; can also mean a fool.
• Antonym理屈りくつNeutralReason or logic, but also strained arguments and excuses; it contrasts with 「理不尽」 only in its sense of sound reasoning.
• Antonym道理どうりNeutralReason, what is right and natural, as in 「道理にかなう」; the direct opposite of 「理不尽」.

Use 「理不尽」 for what is utterly without reason and impossible to accept, as in 「理不尽な要求」 or 「理不尽な死」. For what merely defies logic, say 「不合理」; for the absurd, 「不条理」; for wild, reckless behavior, 「無茶」. The colloquial 「目茶目茶」「滅茶苦茶」「無茶苦茶」 stress chaos and excess; 「馬鹿馬鹿しい」 and its kin, silliness; 「非常識」, lack of common sense; and 「荒唐無稽」, baseless fantasy. The antonyms are 「道理」 and, in its reasonable sense, 「理屈」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 道理どうりにあわないこと。無理むり無体むたい。